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Renix crank, no start issue

brolly

NAXJA Forum User
I'm stumped on the issue. I was driving my xj down the highway going about 45~mph. And it just died out of no where. I saw it was out of gas so i walked to the store and got 2 gallons of gas, poured it into my fuel tank. tried to fire it up, no luck. Got a tow home. Next day noticed the the fuel pump was dead. Replaced it tried to fire it up no luck. I've scoured the forms to try and find a solution and I was convinced it was the cps. replaced it to no luck once again. I have fuel pressure once again but I don't have spark at the ignition coil. the problem is I don't know where to go from here.all that's left is the tps, c101 and igintion coil, correct? 88xj
 
Did you do the CPS modification to boost the output signal while cranking yet?

Check the AC cranking volts of the disconnected CPS while cranking, on the lowest AC volts scale. IT must read at least 0.50 volts, if not it is bad or it needs to have the mounting holes in the CPS made larger so you can move the CPS closer to the flex plate teeth too get a higher voltage, enough voltage for the ECU to see it and to decide to make a spark.

Hard to believe a fuel pump, CPS and a third ignition system component died at the same time. How did you verify the old fuel pump was bad?

Welcome to NAXJA!!! Nice to see another Renix XJ alive and well.
 
Thank you I love the obsession lol mostly self taught haha. The fuel pump did not make even the slightest of sounds and it's usually for lack of a better word noisy. after I replaced it its back to the same noise level, I hope that makes sense.I haven't did that yet I was hoping to avoid that. I figured they all didn't go out either I thought I was just hitting the wrong issue
 
Have you verified you have fuel pressure? Press the Schraeder valve and see if gas spirts out when the key is first turned on.
 
Question, Could I just drill out the CPS unit one size bigger and leave the mounting holes the same. so that the cps will hang down a tad lower, and the bolts will hold it down?
 
Yes sir I have verified fuel pressure. Although I just tested the new Cps at crank, it's hitting around .4 AC.

I have an 87 with the notorious C-101 connector still unmolested, and the CPS was giving me only .27 volts and while it took 6 seconds to start it always started for years. It is now about .52 Volts with the new modified CPS and it starts faster and always starts. Replaced it when I replaced the transmission 9 years ago.

The 89 drove me nuts till I installed a new modified CPS. Even at about .4 volts it would not start far more often that it would start. New modified CPS and about .53 volts cranking at the CPS and it always starts right up. Both have been DDs for ages now. I was also picky about the parts vendor. Did not use autozone, got a Standard brand made in Italy from Rock auto. Many recommend the dealer part.
 
Question, Could I just drill out the CPS unit one size bigger and leave the mounting holes the same. so that the cps will hang down a tad lower, and the bolts will hold it down?

Yes, do not touch the transmission case mounting threaded holes. Just use one drill size large drill bit to increase the hole size on the CPS itself, then push the CPS down from the top as you tighten the bolts. It takes very little change to get a huge jump in voltage.

A little trivia once the engine is running the CPS voltage is about 5-7 volts. It increases with the engine rpm.
 
You're a legend man. but just for a quick cheat what size drill bit should I get?

One size larger than what fits in the present hole. May be 3/8" but I do not recall. I just used the next larger one in my drill bit set like others, 5-90 and Cruizer54, told me to use. I am just sharing what they taught me on the CPS fix. Thanks for the kind words.
 
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